1. Field of the Invention
With respect to the classification of art as established in and by the U.S. Patent Office, this invention is believed to be found in the general class of package making and, in particular, to apparatus and a method for forming a cavity in a thermoformed plastic strip, filling said cavity, and then sealing this filled cavity by another film which is sealed to the filled carrier and then severing this filled and sealed package.
2. Description of the Prior Art
Form-seal-and -wrap apparatus is well known and many U.S. patents showing apparatus and methods and also not the subject of patents are known in the industry. A pre-ex search in the art was made, but certain portions of this apparatus and method are believed to be novel. Among the patents found in this search were U.S. Pat. No. 2,879,635 to BROCK, as issued Mar. 31, 1959, which is one of the basic apparatus for forming, filling and sealing products. This apparatus contemplates a carrier band having spaced apertures. This apparatus does not contemplate adjustability and does not have the desired flexibility and versatility provided by Applicant's invention. U.S. Pat. No. 3,045,403 to MITCHELL, as issued July 24, 1962, provides web advancing mechanism and gripping means for positive advancement, but essentially this apparatus is for articles of clothing in web stock which is quite flexible.
U.S. Pat. No. 3,267,639 to OLLIER et al, as issued Aug. 23, 1966, shows a form, fill and seal apparatus similar to the BROCK apparatus but without a belt conveyor. Advance of the upper and lower films is by a reciprocated member. Clamping and release is by a jack pneumatically actuated. This clamping advances both films after package sealing is achieved. Also noted was U.S. Pat. No. 3,577,700 to BIPPUS, as issued May 4, 1971, which is similar to other apparatus, but uses a punching action to determine a desired spacing of the cutting action. This patent shows a deep draw of a lower thermoformed sheet which is cut into short members before forming. This transport is by a conveyor, but punching and cutting employ a procedure that does not provide the apparatus in the present invention.
U.S. Pat. No. 3,767,349 to JEZUIT, as issued Oct. 23, 1973, is a packaging machine wherein films are fed from supply rolls as in prior devices. This patent is noted in that adjustable guide means is provided for accommodation of different widths of film. U.S. Pat. No. 4,008,554 to HARDY, as issued Feb. 22, 1977, shows a meat product sealed between two films. Forming as provided is shown in both upper and lower films. U.S. Pat. No. 4,068,448 to MODEEN, as issued Jan. 17, 1978, employs opposed rollers having relieved central portions and a power means with a one-way clutch drive. U.S. Pat. No. 4,490,963 to KNUDSEN, as issued Jan. 1, 1985, is another form, fill and sealing apparatus where reliability of a precise cutting of the resulting package strip is provided by a timing cam shaft.
Also noted was U.S. Pat. No. 4,548,018 to WOJNICKI, as issued on Oct. 22, 1985, which shows apparatus for forming, filling and sealing film pouch material. It is to be noted that the cover material is delivered on a separate delivery means and then is transferred to the sealing station. This is to prevent weight discrepancy. U.S. Pat. No. 4,549,386 to WILSON, as issued Oct. 29, 1985, shows another version of a form, fill and seal apparatus. It is to be noted that the sealing jaws are adapted to seal a package as a film overwrap.
It is to be noted that apparatus in this field is well shown in the list of cited reference patents in No. 4,548,018 noted above and in many variations thereof. In the above-noted patents and in other patents and apparatus presently available commercially, the apparatus is required to package a succession of articles or items which are nominally of like size. Often such apparatus provide means for changes in product size and usually for a run in which the product is of the same size. The change in size requires a change in settings and often apparatus components. Changing settings usually involves considerable effort on the attendant's behalf to accommodate these required changes. In the apparatus described hereinafter, the apparatus provides a simple adjustment which makes for the desired size change for those items which are to be wrapped and sealed. The hereafter-described apparatus does not contemplate speed changes and/or drives, although changes in drive mechanism are often required in other known apparatus. These changes are unlikely to be achieved by a simple and easily achieved adjustment as is provided in the described apparatus of this invention.
To establish synchronism of the several elements used in known apparatus, differential gearing, timing belt and pulleys and the like are provided and require extended time periods with procedures to insure fine adjustment of synchronism during routine operation of the machine apparatus. Differential gearing when and where used is complex, requiring a multiplicity of parts which are expensive to manufacture. Changing the apparatus to accommodate another product size has hitherto been an operation performed by a technician or engineer. The present invention provides a simplification of adjustment so that changing the wrapping procedure is easily performed and it is feasible for such changes to be made by the attendant of the machine apparatus.
In many of the previously known and supplied horizontal form-fill-seal wrapping apparatus, rotary forming and sealing dies or jaws are employed, particularly for transverse sealing of the wrapper web between successively wrapped product items. A seal of adverse quality results where or when rotary sealing jaw speed is markedly different from the wrapper speed. Rotating sealing jaws which are caused to rotate in synchronism move at substantially the speed of advance of the wrapping web. A speed change for a change in the wrapping of a product changes the period of time. The present invention provides forming and sealing dies in which changes in web speed, packagage forming and sealing do not adversely affect the seal of the product in the wrapping.
The present invention and the apparatus provided are intended to be adjusted by the attendant of the machine. The form-and-sealing stations are easily changed to accommodate the filling of the formed recess in the bottom film. Film advance is simple and positive and does not provide sudden starts and stops. The length of the advancing stroke is easily changed and provides a means for precise length of package of the wrapped product. The width of the roll supply is easily accommodated and replacement of an empty core with a full spool is also very easily accommodated.